Block parameters in Ruby - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of block parameters with multiple variables

What is the output of this Ruby code?

Ruby

def test
  yield(1, 2)
end

result = []
test do |a, b|
  result << a + b
end

puts result.first

A 2

B 1

C nil

D 3

💡 Hint

Remember that block parameters receive values passed by yield in order.

The method yields two values, 1 and 2, which are assigned to a and b respectively. Adding them gives 3.

❓ Predict Output

intermediate

Block parameters with array destructuring

What will this Ruby code print?

Ruby

def example
  yield([10, 20])
end

example do |(x, y)|
  puts x * y
end

A 10

B 1020

C 200

D Error

💡 Hint

The block parameter uses parentheses to destructure the array.

The array [10, 20] is destructured into x=10 and y=20, so x * y is 200.

❓ Predict Output

advanced

Block parameters with default values

What is the output of this Ruby code?

Ruby

def call_block
  yield(5)
end

call_block do |a, b = 10|
  puts a + b
end

A 15

B Error

C 5

D 10

💡 Hint

Check how default values work in block parameters when fewer arguments are passed.

Only one argument (5) is passed, so a=5 and b uses default 10. Sum is 15.

❓ Predict Output

advanced

Block parameters with splat operator

What will this Ruby code output?

Ruby

def run_block
  yield(1, 2, 3)
end

run_block do |a, *rest|
  puts rest.sum + a
end

A Error

B 6

C 3

D 5

💡 Hint

The splat operator collects remaining arguments into an array.

a=1, rest=[2,3], sum of rest is 5, plus a is 6.

❓ Predict Output

expert

Block parameters with nested destructuring and default values

What is the output of this Ruby code?

Ruby

def complex
  yield([1, 2], 3)
end

complex do |(a, b = 5), c|
  puts a + b + c
end

A 6

B 7

C Error

D 8

💡 Hint

Look carefully at how default values apply inside nested destructuring.

The first argument is [1,2], so a=1, b=2 (default 5 ignored because array provides value), c=3. Sum is 1+2+3=6.